HDMI not working

[frank-w]

added hdmi-nodes from 4.4.70 in hdmi-branch, but kernel seems not to be loaded (debug-uart stops after "Starting kernel ..."-message from uboot)

https://github.com/frank-w/BPI-R2-4.14/commits/hdmi

[jfdelnero]

In mt7623.dtsi :

Enabling all these sections in the same time :

smi_common,
mipi_tx0,
iommu,
mali,
display_components,
color,
dsi0,
mutex,
vdecsys,
larb0,
larb1,
larb2,
imgsys

Doesn't crash the BPI R2 but after enabling one of these sections :

disp_rdma0,
disp_rdma1,
wdma,
ovl

the kernel doesn't boot anymore.

[jfdelnero]

In mt7623n-bananapi-bpi-r2.dts

After enabling all disabled sections :
vdd_fixed_vgpu_reg,
&mali,
mipi_dsi_pin,
and
&mipi_tx0

with all the working sections in mt7623.dtsi listed in my previous post, the kernel still working.

The problem seems to be around disp_rdma0, disp_rdma1, wdma and ovl.
the presence of the iommus references seems to be a common point here.

[frank-w]

good to know, but i assume there is still missing driver-code outside the dts(i)...somewhere in drivers/...

[jfdelnero]

new test :

Reactivate all drivers/sections but comment the iommus = <&iommu > references into disp_rdma0, disp_rdma1, wdma and ovl make the kernel working.
Now it's time try to understand why ;)

[jfdelnero]

rdma0, rdma1, and ovl seems to be now present.

[frank-w]

did you changed anything except enabling the nodes? ok, you've disabled the iommu-ref

[jfdelnero]

Yes exactly. But of course this doesn't make the hdmi working. iommu is needed here.

[frank-w]

i assume that iommu needs a driver in drivers-directory of kernel...maybe you can found one in the 4.4.70-repo

[jfdelnero]

well linux-mt/drivers/iommu/mtk_iommu_v1.c seems to be a good candidate.

[frank-w]

https://github.com/frank-w/BPI-R2-4.14/blob/main/drivers/iommu/mtk_iommu.c exists also in 4.14...mhm. you can compare this with the 4.4-file...maybe something is changed in h-file too

[jfdelnero]

yes just see this too. and there is a mtk_iommu.c too, not compiled here.

[frank-w]

maybe some of these 4.4-options are missing in my config:

CONFIG_IOMMU_API=y
CONFIG_IOMMU_SUPPORT=y
CONFIG_IOMMU_IOVA=y
CONFIG_OF_IOMMU=y
CONFIG_IOMMU_DMA=y
# CONFIG_MTK_IOMMU is not set
CONFIG_MTK_IOMMU_V1=y

CONFIG_IOMMU_API, CONFIG_IOMMU_SUPPORT, MTK_IOMMU_V1,CONFIG_OF_IOMMU are set in my kernel as a see,

CONFIG_IOMMU_IOVA and CONFIG_IOMMU_DMA seems missing

[jfdelnero]

mtk_iommu.c doesn't seems to be compiled too in the 4.4.70.
i will check the options.

[jfdelnero]

Here is what i have with the 4.14

CONFIG_ARM_DMA_USE_IOMMU=y
CONFIG_ARM_DMA_IOMMU_ALIGNMENT=8
CONFIG_IOMMU_HELPER=y
CONFIG_IOMMU_API=y
CONFIG_IOMMU_SUPPORT=y
# Generic IOMMU Pagetable Support
# CONFIG_IOMMU_IO_PGTABLE_LPAE is not set
# CONFIG_IOMMU_IO_PGTABLE_ARMV7S is not set
CONFIG_OF_IOMMU=y
# CONFIG_MTK_IOMMU is not set
CONFIG_MTK_IOMMU_V1=y

CONFIG_IOMMU_IOVA & CONFIG_IOMMU_DMA seems to be missing, or maybe they have been renamed...